Drier



April 14, 1953 H. F. lRvlNG 2,634,512

DRIER Filed Sept. 25, 1948 i 4 Sheets-Sheet 2 INVENTOR. H6777? XVI-rra H. F. IRVING April 14,v 1953 DRIER 4 sheets-sheet z' Filed Sept. 23, 1948 In. l N. Wwlllliiy April 14, 1953 H. F. lRvlNG 2,634,512

DRIER Filed Sept. 23, 1948 4 Sheets-Sheet 4 INVENTOR. #e7-z?? 1T/frying.

Patented Apr. 14, 1953 UNITED STATES PATENT OFFICE DRIER Henry F. Irving, Saginaw, Mich., assigner to Baker Perkins Inc., Saginaw, Mich., a corporation of New York Application September 23, 1948, Serial No. 50,856

9 Claims. (Cl. 3458) sodium chloride, ammonium phosphate and the like. there is a great need for an economical, compact machine or device which will completely dry the salt from its initial slurry state, wherein a large percentage of water is mixed with the solid material, in a rapid and eflicient manner. While centrifugal separators satisfactorily re rn'ove the major portion of the liquid from a slurry, there is a residual film of liquid on the solid particles which cannot be removed by centrifugal action. Accordingly, it is the general object of the present invention to provide means to completely dry solid materials containing minor quantities of liquid and which, therefore, is effective to complete the drying of slurres or the like which have been partially dried by other forms of driers, such as a centrifugal.

In applicants copending application on Rotary Drier, Serial No. 49,613, led September 16, 1948, is disclosed a machine for completing the drying of a slurry which has been partially dried by prior treatment. That machine is adapted by the action of hot 'gases to complete the drying of material containing ten per cent (10%) of liquid -or less and is readily adjusted to remove varying quantities of moisture. It is found, however, that4 in some cases, particularly when the preliminary drier is of the centrifugal type, the moisture content of material is only two per cent (2%) or less. In such cases, the final drying by hot gases may be effected in a very brief period. Accordingly, it is the general object of the present invention to provide an improved and simplified machine for drying materials which contain approximately two per cent (2%) moisture or less by the action of hot gases.

It isa further object of this invention to provide in apparatus of the aforementioned type a more or less cylindrical chute into which partially dried solid materials are rotatably and axially fed While heated air is passed therethrough so as to dry the material as it moves along a helical path from the inlet end to the discharge end a lining of water repellent and abrasive and heat i resistant material so that the solid materials discharged into said chute will not adhere to the Walls thereof.

It is a further object of this invention to provide apparatus of the aforementioned type which includes an improved stationary chute adapted to be directly associated with a centrifugal drier in such a manner that the partially dried material is fed into the chute and moved helically therethrough as the result of the speed of discharge of the material from the rapidly rotating centrifugal.

It is a still further object of this invention to v provide, in a chute of the aforementioned type. means for engaging and reducing the speed of the material discharged into the chute from the partial drying device prior to the engagement of the material with the peripheral wall of the chute, so as to prevent any abrasive wearing of the peripheral wall lining.

It is a still further object of this invention to provide, in conjunction with deiiecting means of the aforementioned type, a coolant jacket adapted to contain a coolant for maintaining the deiecting means at a predetermined temperature, so as to eliminate any tendency for the material discharged into said chute to dry on and adhere to said deecting means.

It is a still further object of this invention to provide a peripheral Wall for a chute of the aforementioned type which is provided with openings through which heated gas may pass from exillustrated in Figure 1 taken along the line 2--2 thereof;

Figure 3 is a sectional view of a further embodiment of the invention illustrating a complete drying machine including a centrifugal drier associated with the preferred form of final drying device; and

Figure 4 is an `end elevational view of the structureillustrated in Figure 3 with parts broken away in section for purposes of clarity.

Referring now to the embodiment of the invention illustrated in Figures l and 2, it will be seen that a feeding mechanism 5 is provided for axially and centrifugally feeding solid materials from a suitable partial drying device into a frustoconically shaped chute 1. The chute 1 is supported by a suitable framework 8 and is surrounded by a housing 3. The feeding device 5 includes a conduit I having a feed screw II therein which axially feeds the material from the partial drying device through the conduit.

In order to impart a rotary and axial motion to the material being discharged from the feeding mechanism into the chute 1, a rotating sleeve I3, having a frusto-conical inner wall I4 and fins I5, is rotatably supported on the framework 8. The outer end of the sleeve I3 overlaps the discharge end of the conduit I so that the solid material will be fed' from the conduit into the sleeve I3. The sleeve I3 is roatably driven at high speed by any suitable means such as a roller I5 which is connected, in a conventional manner, with suitable driving means and which frictionally engages an annular ring or track 2l on outer periphery of the sleeve I3. The material, therefore, will be moved from the partial drying device by the feed mechanism 5 and will be discharged from the sleeve I3 into one end of the chute 1 with a high velocity tangentially of sleeve I3 which will cause the material to slide through the chute in a helical path.

The chute 1 is formed with a frusto-conical peripheral wall 25 which is smaller in diameter at the inlet end of the chute than at the opposed discharge end thereof. The peripheral wall 25 is made up of a plurality of axially overlapping, radially spaced, concentric rings 21, such as illustrated and described in applicants above-mentioned copending application, Serial No. 49,613. The rings 21 are connected together by means of a plurality of circumferentially spaced securing members 23 which have the inner faces thereof axially stepped at 3I so that the rings 21 can be secured thereto in the aforementioned overlapping and spaced relationship by means of countersunk screws 33. The securing members 29 thus support and secure the rings in the aforementioned relationship so as to provide air passageways 35 between thel overlapping portions thereof through which gases may pass for drying the material which moves through the chute 1. It will be noted that the air passageways 35 eX- tend substantially parallel to the axis of the drum andface the outlet end thereof.

The chute housing 9 is provided with a suitable gas inlet passageway or conduit 31 (Figure 2), through which heated gas is conducted into the space within the housing around the outer periphery of the chute 1. The heated gas then passes through the air passageways 35 in the peripheral wall of the chute 1 so as to dry the material moving therethrough. A suitable gas outlet conduit or passageway 39 is provided in the upper portion of the housing 9 so that the gas which passes into the chute 1 will flow out of the open end thereof into the outlet passageways 35. The gas may then be reheated and recirculated, so as to reduce the users power and fuel costs. The housing 9 likewise is provided, adjacent the outlet end of the chute 1, with a material discharge chute or passageway 4I into which the dried material from the chute is discharged.

In operation, the partially dried material from the partial drying device is fed into the inlet end of the chute 1 by means of the feed mechanism 5, previously described. The material will then engage the chute peripheral Wall 25 and slide helically at high speed thr-ough the chute and be held in contact with the walls by centrifugal force until it reaches the discharge end of the chute, even though the chute, itself,l is not rotated. The heated gas passes through the'air passageways 35 and the material moving through the chute. In this way heated gas is passed through the material throughout its entire movement through the chute and the material will be completely dried by the time it reaches the outlet end of the chute and is discharged into the material discharge passageway 4I. The flow of the gases through the wall passageways 35 and the frusto-conical shape of the inner wall I4 of the rotating sleeve I 3 aid in imparting the axial component of movement to the material fed into and moving through the chute.

By forming the chute peripheral wall in the aforementioned manner and by feeding the material helically through the chute athigh speed; the material will slide along the inner wall'of the chute in a thin layer without sticking to the Wall surface, and the flow of hot gas through the rapidly moving thin layer will effect complete drying of the material by the time it reaches the discharge end of the chute 1. Furthermore, vby overlapping and spacing the peripheral Wall, rings 21, the air spaces through which the heat passes Y will not become clogged by the material moving through the chute. It will thus be seen that the drying device is especially simple in construction by making it unnecessary to rotate the chute.

Even the feeding -device may be omitted if the drier;` is used to complete the, drying of material discharged from a centrifugal separator of the continuous discharge type, sinceA in that case, the material discharged from the centrifugal already has the requisite velocity. In this case, the lrotating drum or basket ofthe centrifugal may oc,- cupy the position of the sleeve I3, in the manner set forth more fully hereinafter.

In the embodiment illustrated in Figures 3 and 4, a centrifugal separator 45 of known construction is illustrated for partially drying the solid materials and feeding them into a slightly modied form drier with the desired high tangential velocity. With the centrifugal separator ofv this device, a slurry of material containing a, large percentage of liquid is fed into an inlet -tube or conduit 49. The slurry flows through the tube 49 into a funnel-shaped member 5I which discharges it into a rotating basket or housingV 53 having a plurality of openings 55 in the peripheral wall thereof through which liquid maybe discharged. A peripheral screen 51' is secured to the housing 53 inwardly of the peripheral wall thereof so as to prevent the solid material from passing through the housing openings 55. The

housing 53 is rotatably driven in anyr suitable manner through a hollow shaft 51 so that the majority of the liquid in the slurry will be centrifugally discharged and separated' from the solid material through the openings 55. The cen.- trifugal separator will, however, not remove all' of the liquid from the solid material. The partially dried material is axially discharged more or less continuously from the open end of the housing 53 past a chamfered lip 58, by means of a reciprocating disk plate 59 which is axially reciprocated in any suitable manner by a shaft 6| which extends through the rotatable shaft 51, a wash water inlet conduit 62 has one end extending into the centrifugal drier for use in cleaning the same.

The chute 41 and centrifugal separator 45 are supported on a suitable stand and framework 63, and housings 64 and B5 enclose the chute 41 and separator 45. The chute 41 is of a generally frusto-conical shape and has its small diameter end disposed adjacent to the centrifugal separator 45 so as to receive the material discharged therefrom and aid in imparting an axial component of motion to the material. The chute 41 is provided with a peripheral wall B6 which is made up of a pair of frusto-conical shaped bands or rings 61 which have their adjacent ends secured in an axially overlapping and radially spaced relationship so as to provide an air passageway 69 between the overlapping portions thereof. If the machine is to be used in drying such materials as salt, it has been found that the relatively high temperature of the drum walls tends to dry out a lm of solid material which adheres tenaciously to the drum walls and so increase the coefficient of friction of the walls that material will not slide freely thereon. Serious clogging of the machine may result in such cases. Accordingly, the inner surface of each of hooplike members 61 is lined with an abrasive-resistant, water repellent material 1l, which will withstand at least 350 F. of heat. The preferred lining material for this purpose is polytetrafluoroethylene, a plastic which is sold under the trade name Teflon, but other suitable materials, such as glass, which have the aforementioned characteristics may be used. Suitable means, such as screws or rivets 16, are employed to secure the lining to the bands or rings G1.

The inlet or small diameter end of thek chute 41 is supported on the framework S3 by means of an annular member 12. The annular member 12 includes a pair of spaced ring portions 1? and 13 which are interconnected by means of a plurality of circumferentially spaced ribs 14. The ring portion 13 is connected to the framework 63 and the ring portion 13 is connected to the inner end of the chute peripheral wall SS so that a plurality of air passageways is provided which connect the inlet end of the chute with the space between the outer periphery of the chute and the housing 64, as will hereinafter appear. The outer or discharge end of the chute 41 is supported on and secured to the housing 64 by a plurality of circumferentially spaced angle brackets 84, so that air passageways are provided around the discharge end of the chute which communicate with the space between the chute 41 and housing B4.

Since centrifugal separators must operate at very high speeds to remove the maximum amount of liquid, the speed at which the material is discharged by the centrifugal is not only higher than necessary but is such as to cause undesirable wear of the lining material 1|. Accordingly, when such linings are required in a machine of the type shown in Figure 3, it is desirable to provide means for reducing the tangential speed of movement of the material as it leaves the centrifugal. In the machine of FigureB, this is accomplished by a deflector'15 positioned in the of the centrifugal separator 45. The deflector l15 is in the form of an annular ring or hoop 16 having an outwardly projecting circumferential flange 11 which is connected to the annular member 12. The annular deflector ring 16 is preferably made of a material such as stainless steel, and has a coolant jacket 18 surrounding the outer periphery thereoif and adapted to contain a coolant for maintaining it at a predetermined temperature which will prevent the solid material from adhering thereto, as will be hereinafter pointed out a suitable coolant conduit is provided, through which coolant can flow to the water jacket. The material which is helically discharged from the centrifugal separator 45 will, therefore, first engage the inner surface of the annular ring 15 before engaging the lining 1l on the peripheral wall E6 of the chute 41. The speed as well as the impact of the solid material against the lining 1| will, therefore, be reduced and will reduce abrasive wearing of the lining.

In order to dry the solid material as it passes from the inlet end to the discharge end of the chute 41, an inlet passage or conduit 8l (Figure 4) is provided in the housing 64 through which heated gas is passed into the space between the peripheral wall of the chute and the housing. The gas, which is heated to approximately 350 F., will then pass through the passageways 69 between the overlapping portions of the chutes peripheral Wall rings 61 and through an annular passageway 83 between the deflector 15 and the centrifugal separator 45, as well as through passageways 85 provided between theinlet end of the chutes peripheral wall and its supporting annular member 12. Also, gas will flow through the passageways at the discharge end of the chute so that heated gas is passed through the solid material at several points as the latter moves through the chute. It will be noted that the heated gas ows into and. through the chute substantially parallel to the axis thereof and, therefore, imparts axial movement to the material in the chute, thus aiding in moving the latter axially from the inlet end to the discharge end of the chute. Thus, the centrifugal drier chainfered lip 58, the frusto-conical shape of the chute 41 and the flow of the gas all aid in imparting the axial component of movement to the material. The gas, after passing through the material within the chute 41, ows out of the discharge end of the chute and into an outlet conduit 89. In this way, a continuous iiow of heated gas passes through the air passageways in the chute so as to completely dry the material passing through the chute.

In operation, the partially dried material isv tangentially and axially discharged from the centrifugal separator 45 into the inlet end. of the chute 41, as previously described. The material will rst engage the inner periphery of the annular deflecting ring 15 and will then engage the` peripheral wall of the chutev and travel along anexpanding helical path toward the chute discharge end. The deflecting ring 15 is maintained,

by means of the coolant in the coolant jacket 19,

at a temperature 4which is high enough to prevent condensation and low enoughto prevent drying of the material thereon which otherwise would be caused by the heat in the chute. The material, after engaging and being slowed up by the annular ring 15, slides helically through the chute without causing abrasive wear on the lining 1I. Due

to the aforementioned characteristics of Ythe lining 1|, the materalwill not adhere thereto but..

will Vmoi/e rapidly through the chute in a thin layer in con-tact with thewalls while the heated gas is passed therethrough so as to completely dry it by the time it is discharged. The material is then discharged from the ohuteinto a discharge passageway or chute 89 in the housing Se and the dried material, such as salt, is ready for its ultimate-use.

The centrifugal separator t5, illustrated in Figure 3, is of previouslyknown construction, but it will be understood that any form of centrifugal separator may be employed with either form of the invention so long as it is capable of discharging the partially dried material continuously over the entire periphery of the open end of the rotating drum or basket.

It will, of course, be appreciated that while only the chute illustrated in Figures 3 and 4 has a lining of water repellent and abrasive and heat resistant material, the chute illustrated in Figures l and 2 may be provided with such a lining and preferably is when the material being dried is salt. It furthermore will be appreciated that g while the chutes and the centrifugal driel1 are illustrated in the drawing as being disposed on a horizontal axis, they could be vertically mounted and discharge either upwardly or downwardly without departing from the spirit and scope of this invention. Likewise; the forms of chutes iliustrated in Figure l may he substituted for that in Figure 3, or vice versa.

What is claimed is:

l. Apparatus for removing liquid from moist solid material, comprising a stationary chute having a surface which is circular in cross section over which said material may helically slide, said chute having openings in said surface, said surface being formed of a material which is water repellent and resistant to heat and abrasion, and

means for directing heated gas through said openthrough the material as it slides helically through f said chute'in contact with the inner wall thereof, said chute having a lining -oi material which' is water repellent. and abrasive and heat resistant on the inner Ysurface of its wall.

3. Apparatus for removing'mcisture from soli-d materials, including a stationary chut-e having a peripheral wall which is circular in cross section, a rotating feeding means adjacent one end of said chute for feeding partially dried material into one end of said chute at a high speed in a circumferential direction whereby the said material slides helically along and in contact with the chute peripheral wall from the inlet end to the opposite endV thereof, said means being circular in crosssection and terminating adjacent one end ofthe peripheral wall of said chute, passageways in said chute wall through which gas can flow into said chute from eXteriorly thereof, and means for directing heated gases from exteriorly of said chute Y through said passageways so as to dry the material moving from the inlet end to thedischarge end of said chute. v Y Y y 4. Apparatus for removing moisture from soli materials,V including a stationary chute'having a materials including a horizontany disposed sta-- tionaryv chute havinga peripheral wall which is i peripheral wall which is circular in cross section, mechanism for feeding partially dried material into one end of said chute with a rotary component of motion and suillcient velocitw to cause the material to slide around the walls of the chute in contact therewith until it is discharged from the other end, a lining on the inner surface of the peripheral wall of said chute of material which is water repellent and abrasive and heat resistant, openings in said chute through which gas may nowV from exteriorly of said chute, and a baille element adjacent the inlet end of said chute adapted to be engaged by the material fed into said chute prior tothe yengagement of said material with the peripheral wall lining thereof.

5. Apparatus for removing moisture from solid materials, including astationary chute having a peripheral wall which is circular in cross section, mechanism for feeding material into one end of said chute with a rotary component of motion and sufficient velocity to cause the material to slide around the walls of the chute in Contact therewith untilV it is discharged from the other end, a lining on the inner surface of the peripheral wall of said chute of material which is water repellent and abrasive andk heat resistant, openings in said chute through which gas may flow from exteriorly of said chute, an annular ring positioned in the inlet end of said chute for engaging and slowing down the material fed into said chute prior to the engagement of the material with said chute peripheral wall lining, and a coolant jacket surrounding said annular ring and adapted to contain a coolant for maintain-V ing said annular ring at a predetermined temperature wherein said material will not stick to said ring.

6. In apparatus for removing moisture from solid materials, a stationary chute having a peripheral wall which is circular in cross section and into one end of which partially dried material may be fed so as to cause it to slide around the wall of the c` ute and in contact therewith until it is discharged from the opposite end, a lining on the inner surface of the peripheral wall of said chute of material which is water repellent and abrasive and heat resistant, said chute wall and lining having openings therein which extend axially of said chute through which heated gases may flow from exteriorly of the chute so as to.

materials including a stationary chute having a v peripheral wall which is circular in cross-section, mechanisn'i for feeding partially dried material into oneA end of said chute at a high speed in a circumferential direction whereby said material slides helically along and in contact with the chute peripheral wall from the inlet end tothe opposite end thereorpassageways insaid chute Wall through which gas can flow into said chute from exteriorly thereof, the inner surface of said chute wall being formed of a material which is f water-repellent and resistant to heat andY abrasion, and means for directing heated gaseslfrom exteriorly" of said chute through said passage-l ways so asv to dry theV material moving from the inlet end to the discharge endof said chute.

8. Apparatus for removingmoisture from-solid 9 circular in, cross-section, mechanism for feeding partially dried material into one end of said chute at a high speed in a circumferential direction whereby said material slides helically along and in contact with the chute peripheral wall from the inlet end to the opposite end thereof, passageways in said chute Wall through which gas can iioW into said chute from exteriorly thereof, and means for directing heated gases from exteriorly of said chute through said passageways so as to dry the material moving from the inlet end to the discharge end of said chute.

9. Apparatus for removing moisture from solid materials including a horizontally disposed stationary chute having a peripheral Wall which is circular in cross-section, mechanism for feeding partially dried material into one end of said chute at a high speed in a circumferential direction whereby said material slides helically along and in contact with the chute peripheral Wall from 10 y said passageways so as to dry the material moving from the inlet end to the discharge end of said chute. Y

HENRY F. IRVING.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 1,431,978 Nesbitt Oct. 17, 1922 1,936,866 Van Ackeren Nov. 28, 1933 2,077,819 Zizinia Apr. 20, 1937 2,254,867 Bonottc Sept. 2, 1941 2,371,619 Hartley Mar, 20, 1945 2,401,754 Green June l1, 1946 2,456,674 Caughey Dec. 21, 1948 FOREIGN PATENTS Number Country Date 306,748 Germany Jan. 26, 1916 OTHER REFERENCES Plastics, Teon makes its debut, pages 32, 33, and 97, July 1946.

Buflovak, Drum Dryers, Bulletin 285, page 15. Buffalo Foundry and Machine Company. 

